Acoustic probes have been found to be extremely valuable in a variety of applications. While medical applications in the form of ultrasound imaging are perhaps the most well-known, acoustic probes are more generally used at a variety of different acoustic frequencies for imaging a variety of different phenomena. For example, acoustic probes may be used for the identification of structural defects, for detection of impurities, as well as for the detection of tissue abnormalities in living bodies. Acoustic probes rely generally on the fact that different structures (e.g., cancerous lesions in a body, defects in an airplane wing, etc.) have different acoustic impedances. When acoustic radiation from an acoustic probe is incident on an acoustic interface, such as where the acoustic impedance changes discontinuously, it may be scattered in ways that permit characterization of the interface. Radiation reflected by the interface is most commonly detected in such applications, but transmitted radiation is also used for such analysis in some applications.
Transmission of the acoustic radiation towards a target and receipt of the scattered radiation may be performed and/or coordinated with a modern acoustic imaging system. Many modern such systems are based on multiple-element array transducers that may have linear, curved-linear, phased-array, or similar characteristics. These transducers may, for example, form part of an acoustic probe. In some instances, the imaging systems are equipped with internal self-diagnostic capabilities that allow limited verification of system operation, but do not generally provide effective diagnosis of the transmission and receiving elements themselves. Degradation in performance of these elements is often subtle and occurs as a result of extended transducer use and/or through user abuse. Acoustic imaging devices therefore often lack any direct quantitative method for evaluating either system or probe performance. Users and technical support personnel thus sometimes use phantoms that mimic characteristics of the object under study to provide a qualitative method for evaluating image quality and to perform a differential diagnosis between the system and the transducer array, but this technique is widely recognized to be of limited utility.
There is, therefore, a general need in the art for apparatus and methods for testing acoustic probes and systems.